This invention relates to a plastic hairdressing comb with teeth and a spine, where the comb contains at least one section which negatively charges the hair during combing and at least one section which positively charges the hair during combing.
When hair is combed with a plastic hairdressing comb, the hair and the comb generally become electrostatically charged in a totally uncontrolled manner, particularly in a dry atmosphere. This makes the hair difficult to comb.
The electrostatic charging of hair during combing is caused by frictional electricity (triboelectric effect). On account of the insulating properties of the comb and the hair, the separate charges are unable to dissipate and lead to charge accumulations of opposite polarity on the hair and the comb. It is possible in this connection to set up a potential series whereby positive charging occurs in the event of rubbing with a substance which follows in the potential series, while negative charging occurs in the event of rubbing with the preceding substance in the potential series. Coehn's law of charging states for insulators that the substance with the higher dielectric constant is positively charged.
Even if one of the substances coming into contact is a conductor, charging of the other substance cannot be completely prevented because at least some of the charged produced on the insulator in the event of rubbing on the conductor remain there. Accordingly, even if a metal comb or a metal-coated plastic comb is used, it is not possible to avoid individually more or less heavy and troublesome electrostatic charging, particularly in a dry atmosphere (and dry hair).